4.12 Preview 3 has been released! This build comes with numerous bug fixes and a look at experimental Vulkan support, high quality post-processing effects for mobile platforms and more.
To download, head over to the Epic Games Launcher and select the "Library" tab. Click "Add Versions" and choose 4.12 Preview 3. If you have a Preview version already installed, simply hit 'Update'.
Read up on the updates specifically included in this release through the latest forum post from Stephen Ellis. Also be sure to have a look at the known issues list to see what's still outstanding. Remember these Preview builds are for testing only, so try not to use them for the active development of your project!